
jQuery.extend(
{
  createUploadIframe: function(id, uri)
  {
    // Create frame.
    var frameId = 'jUploadFrame' + id;

    if (window.ActiveXObject)
    {
      var io = document.createElement('<iframe id="' + frameId + '" name="' + frameId + '" />');
      if (typeof uri == 'boolean')
      {
        io.src = 'javascript:false';
      }
      else if (typeof uri == 'string')
      {
        io.src = uri;
      }
    }
    else
    {
      var io = document.createElement('iframe');
      io.id = frameId;
      io.name = frameId;
    }
    io.style.position = 'absolute';
    io.style.top = '-1000px';
    io.style.left = '-1000px';

    document.body.appendChild(io);

    return io
  },
  createUploadForm: function(id, fileElementId)
  {
    //create form	
    var formId = 'jUploadForm' + id;
    var fileId = 'jUploadFile' + id;
    var form = $('<form  action="" method="POST" name="' + formId + '" id="' + formId + '" enctype="multipart/form-data"></form>');
    var oldElement = $('#' + fileElementId);
    var newElement = $(oldElement).clone();
    $(oldElement).attr('id', fileId);
    $(oldElement).before(newElement);
    $(oldElement).appendTo(form);
    //set attributes
    $(form).css('position', 'absolute');
    $(form).css('top', '-1200px');
    $(form).css('left', '-1200px');
    $(form).appendTo('body');
    return form;
  },

  ajaxFileUpload: function(s)
  {
    // TODO introduce global settings, allowing the client to modify them for all requests, not only timeout		
    s = jQuery.extend({}, jQuery.ajaxSettings, s);
    var id = new Date().getTime()
    var form = jQuery.createUploadForm(id, s.fileElementId);
    var io = jQuery.createUploadIframe(id, s.secureuri);
    var frameId = 'jUploadFrame' + id;
    var formId = 'jUploadForm' + id;
    // Watch for a new set of requests
    if (s.global && !jQuery.active++)
    {
      jQuery.event.trigger("ajaxStart");
    }
    var requestDone = false;
    // Create the request object
    var xml = {}
    if (s.global)
      jQuery.event.trigger("ajaxSend", [xml, s]);
    // Wait for a response to come back
    var uploadCallback = function(isTimeout)
    {
      var io = document.getElementById(frameId);
      try
      {
        if (io.contentWindow)
        {
          xml.responseText = io.contentWindow.document.body ? io.contentWindow.document.body.innerHTML : null;
          xml.responseXML = io.contentWindow.document.XMLDocument ? io.contentWindow.document.XMLDocument : io.contentWindow.document;

        } else if (io.contentDocument)
        {
          xml.responseText = io.contentDocument.document.body ? io.contentDocument.document.body.innerHTML : null;
          xml.responseXML = io.contentDocument.document.XMLDocument ? io.contentDocument.document.XMLDocument : io.contentDocument.document;
        }
      } catch (e)
      {
        jQuery.handleError(s, xml, null, e);
      }
      if (xml || isTimeout == "timeout")
      {
        requestDone = true;
        var status;
        try
        {
          status = isTimeout != "timeout" ? "success" : "error";
          // Make sure that the request was successful or notmodified
          if (status != "error")
          {
            // process the data (runs the xml through httpData regardless of callback)
            var data = jQuery.uploadHttpData(xml, s.dataType);
            // If a local callback was specified, fire it and pass it the data
            if (s.success)
              s.success(data, status);

            // Fire the global callback
            if (s.global)
              jQuery.event.trigger("ajaxSuccess", [xml, s]);
          } else
            jQuery.handleError(s, xml, status);
        } catch (e)
        {
          status = "error";
          jQuery.handleError(s, xml, status, e);
        }

        // The request was completed
        if (s.global)
          jQuery.event.trigger("ajaxComplete", [xml, s]);

        // Handle the global AJAX counter
        if (s.global && ! --jQuery.active)
          jQuery.event.trigger("ajaxStop");

        // Process result
        if (s.complete)
          s.complete(xml, status);

        jQuery(io).unbind()

        setTimeout(function()
        {
          try
          {
            $(io).remove();
            $(form).remove();

          } catch (e)
          {
            jQuery.handleError(s, xml, null, e);
          }

        }, 100)

        xml = null

      }
    }
    // Timeout checker
    if (s.timeout > 0)
    {
      setTimeout(function()
      {
        // Check to see if the request is still happening
        if (!requestDone) uploadCallback("timeout");
      }, s.timeout);
    }
    try
    {
      // var io = $('#' + frameId);
      var form = $('#' + formId);
      $(form).attr('action', s.url);
      $(form).attr('method', 'POST');
      $(form).attr('target', frameId);
      if (form.encoding)
      {
        form.encoding = 'multipart/form-data';
      }
      else
      {
        form.enctype = 'multipart/form-data';
      }
      $(form).submit();

    } catch (e)
    {
      jQuery.handleError(s, xml, null, e);
    }
    if (window.attachEvent)
    {
      document.getElementById(frameId).attachEvent('onload', uploadCallback);
    }
    else
    {
      document.getElementById(frameId).addEventListener('load', uploadCallback, false);
    }
    return { abort: function() { } };

  },

  uploadHttpData: function(r, type)
  {
    var data = !type;
    data = type == "xml" || data ? r.responseXML : r.responseText;
    // If the type is "script", eval it in global context
    if (type == "script")
      jQuery.globalEval(data);
    // Get the JavaScript object, if JSON is used.
    if (type == "json")
      eval("data = " + data);
    // evaluate scripts within html
    if (type == "html")
      jQuery("<div>").html(data).evalScripts();
    //alert($('param', data).each(function(){alert($(this).attr('value'));}));
    return data;
  }
})

